1. Field of the Invention
The present invention relates to a recovery system applicable to an ink jet recording apparatus, etc., and to an ink jet recording apparatus provided with said recovery system.
2. Related Background Art
Conventionally, a recording apparatus, such as a printer, a copier, a facsimile, etc., is of such a construction that an image formed with dot patterns is recorded on a recording sheet, such as paper, thin plastic plate, etc., by driving the energy generating member of a recording head in accordance with image information being received.
An ink jet recording apparatus used as such a recording apparatus has an advantage that the noise at the time of recording is extremely small and that a high-density multi-discharging port can be mounted with ease, thereby making it possible to perform high-speed recording. Also with ink jet recording, it is easy to perform color reproduction of a color image, so this type of recording apparatus is increasingly becoming of interest to those in the art recently.
Particularly, with a method of discharging ink droplets to eject with the utilization of heat energy, in which flow passages can be formed by thin film technique, it is possible to obtain a high density most easily among all recording methods. Such method, therefore, is just suited to high-speed recording.
As an example of recording head employed for an ink jet recording apparatus such as this, there is a recording head having a plurality of discharging ports formed across the entire recording width of recording sheet, i.e., a recording head of the socalled full line type.
Each of the aforesaid plural discharging ports is connected to a common liquid chamber built inside of the recording head. To this common liquid chamber, a plurality of ink supply tubes (two, for example) are connected from an ink tank storing ink to be supplied to the recording head in such a fashion that at the time of recording ink is supplied from both of the supply tubes while at the time of a recovery operation for the recording head, one-way flow of ink is generated in the direction sequentially towards the ink tank, one of the supply tubes, recording head, the other supply tube, and back to ink tank.
Nevertheless, due to ink evaporation and drying, stains caused by ink leakage and adhesion of dust, generation of air bubbles in the ink supply passages, or the like, the ink jet recording head may be subjected to defective ink discharging, and there is a possibility that the quality of recorded image is lowered. In order to prevent this defective discharging, it is necessary to clean off the discharging ports of the head with a blade or to perform discharging of ink from all of the ports just for cleaning purposes during recording or at the time of off recording, or it is required to perform the recovery operation for the recording head by performing the aforesaid one-way flow of ink among others. There is also a need for tightly closing the discharging ports when the head is not in use. To this end, capping means should be provided, and its structure should be arranged so as to enable the recording head to move from the recording position for capping.
Conventionally, as means to construct the recovery means, capping means is used for tightly closing the nozzles of an ink jet head.
Here, the cap of a capping means is made of plastic material such as rubber, etc., and when an ink jet printer is not performing a recording operation, such cap is pressed against the ink jet head to tightly close the nozzle section to keep it from the atmosphere for preventing drying. In this instance, the aforesaid tight closure is effectuated by causing the faces of the cap and ink jet head to be in contact with each other.
For the conventional recording head of full line type, however, there is a problem that it is difficult to press discharging ports with a closed space provided by a cap while a member for pressing the discharging ports should be maintained in parallel with the cap stably and accurately.
Also, as another means to construct the recovery means, there is traditionally known wiping means to clean off ink adhered to the face of the orifice of an ink jet head. This wiping means is of such a structure that ink is cleaned off by moving the face of the orifice of the ink jet head in a direction at right angles to the wiper.
However, since many discharging ports are generally provided on the orifice face, there arises a problem that the recorded image is adversely affected. Further, if the hardness of the wiper is enhanced or the thickness thereof is increased, the contacting pressure between the wiper and the orifice face becomes greater. Then, the wiper itself is worn by friction, and ink cannot be cleaned off where the portion of wiper has been worn out. Hence, a problem is encountered that a defective image is also produced.